map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

server {
    listen 80;
    listen [::]:80;
    server_name _;

    root /usr/share/nginx/html;
    index index.html;
    # Matches the default API allowance of twenty 25 MiB files plus multipart
    # overhead. Keep this in sync if the backend upload limits are raised.
    client_max_body_size 512m;

    resolver 127.0.0.11 valid=10s ipv6=off;
    set $api_origin http://api:7532;

    location ~ ^/(api|health|media)(/|$) {
        proxy_pass $api_origin;
        proxy_http_version 1.1;
        proxy_connect_timeout 5s;
        # Multipart requests return only after image processing and private-S3
        # writes complete. This is an inactivity timeout, not a size limit.
        proxy_read_timeout 10m;
        proxy_send_timeout 10m;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    location /socket.io/ {
        proxy_pass $api_origin;
        proxy_http_version 1.1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_buffering off;
        proxy_read_timeout 75s;
    }

    location / {
        try_files $uri $uri/ /index.html;
    }
}